1. Field of the Invention
The present invention relates to a laminated film for thermosensitive image transfer material. More particularly, the present invention relates to a laminated film for thermosensitive image transfer material having excellent hot sticking resistance even in a high energy-applied range, slidability; and printability.
2. Description of the Related Art
Thermosensitive image transfer materials including an ink layer that is melted or sublimated by applying a heat have been widely used for applications such as printing with word processors, bar codes, and facsimiles. In recent years, it becomes possible to form an image with high precision like a silver halide photographic materials, using such thermosensitive image transfer materials including the ink layer that is melted or sublimated by applying a heat.
The thermosensitive image transfer material typically comprises a polyester film as a base film. If the thermosensitive image transfer material comprising a bare polyester film is used for printing, the film is unfavorably fused and stuck to a thermal head by a heat of the thermal head. This is called xe2x80x9chot sticking phenomenonxe2x80x9d. If the hot sticking phenomenon occurs, the thermosensitive image transfer material does not run smoothly, and the thermal head is contaminated, resulting in insufficient sharpness of a print. In order to overcome the hot stick phenomenon, a heat-resisting protective layer is disposed at a surface of the polyester film where the thermal head is contacted, i.e., the surface being opposite to a thermal image transfer ink layer of the polyester film. A material of the heat-resisting protective layer includes a silicone-based composition,sa fluorine-containing composition, a wax-based composition, and various thermosetting compositions.
Current printer technologies direct to a full color high precision, and high-speed printing. Corresponding to the tendencies, high energy is applied to the printer. For example, Japanese Unexamined Patent Application Publication No. 55-7467 describes a silicone-based, melamine-based, or phenol-based heat-resisting protective layer. The thermosensitive image transfer material including such conventional heat-resisting protective layer has insufficient slidability to the thermal head heated, whereby the hot stick phenomenon occurs. Japanese Unexamined Patent Application Publication No. 56-155794 describes a heat-resisting protective layer including an inorganic pigment. The thermosensitive image transfer material including such conventional heat-resisting protective layer can shorten a life of the thermal head by an abrasion with the thermal head, and may have a roughened surface to decrease thermal conductivity. No sharp print may be provided. Japanese Unexamined Patent Application Publication No. 60-192630 describes a heat-resisting protective layer containing a fluorine-contained resin. The thermosensitive image transfer material including such conventional heat-resisting protective layer has insufficient slidability to the thermal head heated, whereby the hot stick phenomenon occurs. Japanese Unexamined Patent Application Publication Nos. 59-148697 and 60-56583 each describe a heat-resisting, protective layer to which a wax component is applied. The thermosensitive image transfer material including such conventional heat-resisting protective layer is fused by a heat of the thermal head to provide adequate slidability. However, the thermosensitive image transfer material cannot provide satisfactory printability using a current high-speed printer, or at a high energy applied range.
U.S. Pat. No. 5,407,724 is a patent about a laminated film for image transfer material including a layer containing a wax-based composition as a main component, and specific protrusions. However, the laminated film for thermosensitive image transfer material cannot provide satisfactory printability using a current high-speed printer, or at a high energy applied range.
The present invention provides a laminated film for thermosensitive image transfer material, comprising a laminated layer containing 50% by weight or more of a wax-based compound, wherein the laminated layer has island-like protrusions, wherein the island-like protrusions have stripe-like protrusions on their surfaces, and wherein a density of the island-like protrusions is 2 to 100 protrusions/100 m2.